Mind "the pause" when sizing

[Hohn]

I've heard of having to pause when sizing as it takes time for the brass to settle in the die. It seemed reasonable to me, but I'd never proven in to myself that it was a good idea or advisable. It was just a theory that made sense.

Until last night.

Sizing a batch of .223 brass. The cases were well lubed and sizing with little effort. But the shoulder bump was inconsistent. Some were 0.001, some were nearly 0.0025. Hmm. I cleaned my die with some brake cleaner and it was still a little inconsistent.

Then I recalled the advice to "pause" at the top of the sizing stroke. I did this for a full 4-5 seconds and suddenly all my case size variation seems to disappear. Measured headspace was as consistent as my comparator will allow me to determine.

So I did an experiment with a heavily lubed case. The forster dies have a vent hole in them and when you insert an overlubed case you can HEAR the lube being pushed out the vent hole for 4 seconds or so in the paused portion of the full stroke. You are literally hearing the brass move as the conditions stabilize. (yes, some of it is just trapped fluid bleeding down, but the brass will move as a result).

I'm sure this is no surprise to many of you. And while I'm not from Missouri, I am a "show me" kind of guy and this experiment satisfied me that if you aren't pausing at the peak of your sizing stroke, you might not be sizing consistently.

 

[PhilC]

Not surprised to read this.

Read about this a year or so ago and recently modified my process. Since I'm not doing large volume loading and use Imperial, I lube a case, raise ram to top hold for 5secs, pick up next case and lube, remove sized case from press and repeat.

I had similar variations in bump prior to employing the pause but now they consistently measure +/- .0005".

 

[Straightshooter1]

Yeah, the dwell time does help! And I will add that how much dwell time might be needed depends a lot on the state of the brass, like whether or not it's been annealed . . . or, how well it's been annealed.

Note too, that one will most often find that there's spring back to the extent that if you measure the neck a day after, the brass will have sprung back a little more. I simply mention this as something reloaders should keep in mind.

 

[AJC]

I have been using 10 seconds as I remove the sized case, size the next one while i measure the base to datum and lube the next case.
Cant immagine anyone using a dillion pauses at all...

 

[Hohn]

I have been using 10 seconds as I remove the sized case, size the next one while i measure the base to datum and lube the next case.
Cant immagine anyone using a dillion pauses at all...

A temptation when using a single stage is to try to optimize productivity, so I can see others doing what I was doing and just slamming it up and down and move on.

I bulk lube my cases in a gallon ziploc with a lanolin homebrew, so I'm just counting on the "pause" and not doing anything productive.

 

[r bose]

I think not annealing will also cause inconsistent should bump. I anneal every 3rd firing. I too am a fan of "the pause" when resizing. I might be overstating but it seems to help with neck tension too. Started doing the pause about 3 months ago and no doubt, it works.

 

[Bill Norris]

This seems to be catching on with hand loaders. Next time I'm sizing I will definitely give it a try. Interesting to read about how it is helping with consistency of brass movement.

 

[AJC]

This seems to be catching on with hand loaders. Next time I'm sizing I will definitely give it a try. Interesting to read about how it is helping with consistency of brass movement.

I got it from joe salt

 

[Papa Charlie]

I find I still have far too much spring back from a pause of 4-5 sec. I under size my necks with bushings, then on the next stroke expand using gauge pin. I wait a count of 10 before lowering. I use a progressive for my sizing, one station for FL sizing, one station for Neck sizing, and one station for the Pin Gauge for final sizing.

 

[Hohn]

I think not annealing will also cause inconsistent should bump. I anneal every 3rd firing. I too am a fan of "the pause" when resizing. I might be overstating but it seems to help with neck tension too. Started doing the pause about 3 months ago and no doubt, it works.

Agree entirely. A sizing operating can only be as consistent as the hardness and composition of the casing. Inconsistent hardness will change how the case responds to forming.

Thus, the ultimate in consistency is achieved when the neck and shoulder a fully hard or fully soft (annealed).

 

[Papa Charlie]

Agree entirely. A sizing operating can only be as consistent as the hardness and composition of the casing. Inconsistent hardness will change how the case responds to forming.

Thus, the ultimate in consistency is achieved when the neck and shoulder a fully hard or fully soft (annealed).

A hard metal will have greater spring back then a soft metal.

 

[Hohn]

Yes it will. But it will be the same springback every time.

 

[AJC]

A hard metal will have greater spring back then a soft metal.

In this game having a consistent amount is of greater importance than how much. If every piece is identical that is more important than hard or soft. Annealing seems to give the most constant results so that's why used.

 

[PopCharlie]

I just started doing this. I anneal after each firing and am using Lapua brass. A 4 Mississippi count seems to be about right for me.

 

[gambleone]

I got it from joe salt

Joe knows.

 

[Iowa Fox]

Good lube and dwell time. Proved it to myself a while back.

 

[ChrisA]

Hmmm, I've been a wam bam resizer. Implementing a 5 second pause would only add 21 minutes to a batch of 250.

Not sure if I can shoot the difference though.

Chris

 

[lb-ft]

I’ add this.

When FL sizing, I don’t dwell but I fully size and cam over, lower the ram just a bit, rotate the case roughly 90 degrees with two fingers, and fully cam over again.

When sizing 338 Lapua, I’ve found the only way to get satisfactory consistency in results is FL sizing twice, about 24 hours between operations. First time though, I leave the expander out, so essentially I only work the necks once.

 

[K22]

Very interesting - amazing - going to try it for sure - makes sense.

Thanks for the post and recommendation.

 

[Coonman300]

Interesting...I noticed a lot of times my shoulder measurement was longer AFTER resizing. I always figured it was the expander ball stretching the brass. I started leaving it in there for a few seconds or sometimes hitting it twice and the problem went away. I’ll just let it sit a few seconds and see what happens